Canada is a country that occupies much of North America and extends from the Atlantic Ocean to the east to the Pacific Ocean to the west. To the north the country is bordered by the Arctic Ocean. It is the second largest country in the world in total area, surpassed only by Russia, and its common border with the United States, in the south and northwest, is the longest terrestrial border in the world. The lands occupied by Canada have been inhabited for millennia by different groups of Aboriginal peoples. Beginning at the end of the 15th century, British and French British expeditions explored and later settled along the Atlantic coast of the country. France ceded almost all its colonies in North America in 1763 after the Seven Years' War. In 1867, with the union of three British colonies of North America in one confederation, Canada was formed as a federal domain of four provinces. This began with an increase of provinces and territories and with a process of increase of autonomy of the United Kingdom. This extension of autonomy was underlined by the 1931 Westminster Statute and culminated in the 1982 Canada Act, which eliminated vestiges of legal dependence of the British Parliament.